The vomeronasal organ (VNO) is a collection of neurosensory cells encapsulated within a bony shell located along the ventral edge of the nasal septum. The neurosensory cells within the VNO project to the accessory olfactory bulbs which lie embedded in the dorocaudal portion of the main olfactory bulbs. In mice, bilateral bulbectomy (i.e., bilateral removal of the main and accessory olfactory bulbs) produces a syndrome of profound social behavioral deficits which includes the elimination of sexual and aggressive behaviors. The research proposed in this application involves cutting the vomeronasal nerves (i.e., the connections between the VNO and the accessory olfactory bulbs) to determine the extent to which the vomeronasal olfactory system is involved in the display of sexual and aggressive behaviors in mice, and to determine the extent to which damage to the vomeronasal olfactory system plays a critical role in the production of social behavioral deficits by bulbectomy.